The purpose of the proposed research is to evaluate the emotional health promotion capability of a causal modeling and intervention strategy for stress prevention. The strategy is aimed at enchancing the development of social competence and minimizing the negative impact of transitional life events in early adolescents. Emotional health will be gauged by prevention of stress and emotional/behavioral disorder. The specific aims include: (1) Validating the impact of transitional life events in early adolescents (e.g., grade and school transitions); (2) testing a causal model of stress based on the direct influence of predisposing, precipitating, and social stressor (negative life events) variables and on the mediating influence of competence, support, and self value; (3) elucidating emotional health trends in adolescents identified as at risk for stress; and (4) evaluating the effects of social competence training on stress prevention. Five cohorts (grades 4 through 8; N=450) will be evaluated each semester for three years on cognitive, affective, and behavioral indices of stress; and independent sample added in Year 2 will provide cross-lagged cohort comparisons (grades 5 through 9; N=675). The overall design is cohort-sequential, with a modified Solomon four-group design subsumed in Year 2. Screening, baseline, pre- and post-training, and follow-up data will provide assessment of normative developmental trends in emotional health as well as maintenance and generalization of training effects. Based on documented transition proneness and social competence need in early adolescents, the central hypotheses are: (1) that negative transitional events should contribute to stress; (2) that social competence in combination with self value and positive social support should reduce direct influences on stress; (3) that social competence training should enhance social competence and therefore prevent or reduce stress; and (4) that stress in combination with low levels of competence, support, and self value should contribute to the onset of emotional/behavioral illness. The proposed research expands the concept of diathesis stress by including mediating influences.